1. Field of the Invention
The present invention relates generally to combustion engines and more particularly to controls for reducing the emissions from the engine exhausts.
2. Description of the Prior Art
In the development of the internal combustion engine for automotive use, the engine has progressed to a high speed reciprocating piston engine having a relatively short piston stroke in the cylinder. In a conventional automobile piston engine, the piston stroke is approximately three inches and the engine operating speed approaches 4800 revolutions per minute. Although such engines are the models of automotive sophistication, a serious shortcoming with such high speed, short stroke engine is that very little of the fuel mixture is burned within the cylinders. The unburned portion of the fuel is emitted from the engine exhausts to contaminate the atmosphere.
Moreover, gasoline manufacturers have added to the smog problem by adding detergents and other chemicals to the gasoline. Although these additives have helped in eliminating engine knock and other problems, a very large percentage of these additives also are expelled into the atmosphere in an unburned condition.
One proposal for reducing emissions is to utilize natural gas in our automobile engines. However, the cost of conversion and the inconvenience in implementing a natural gas system would be prohibitive.
Another proposal for reducing emissions is to preheat and vaporize the gasoline as it enters the intake manifold of the engine. Although such a modification would be advantageous, gasoline vaporization alone will not be sufficient to reduce emissions to an acceptable degree.